Adhesives exist in many forms, from typical liquids which turn to solids between the surfaces to be joined, to a special class known as hot-melt adhesives. Hot-melt adhesives are those which can be melted and applied in molten form to a body to be held to another body. Bond strength develops merely by cooling the molten adhesive to the solid state.
Hot-melt adhesives presently available are not convienient to use since they require both means to heat the adhesive to the melting point and means to apply the molten adhesive to the work piece. Various apparatus which place a hot-melt adhesive in proximity with heating means have been developed and are shown in U.S. Pat. No. 3,505,261, for example. Such apparatus, of course, greatly increases the cost of use of hot-melt adhesives and limits the use of hot-melt adhesives to only those locations with electrical outlets since electricity is required to energize the heating element of the melting apparatus. Also, some facility with mechanical apparatus is required to operate the melting apparatus and adhesive supply in a proper manner, another factor limiting the usefulness of such products.
On the other hand, because hot-melt adhesives offer the advantage of being extremely fast-setting and represent a means of applying an adhesive to hard-to-reach areas, there is considerable interest in developing easy-to-use hot-melt adhesives.
It is an object of this invention to provide a hot-melt adhesive with self-melting capability which does not require external heating means, is simple to use and economical to produce, and yet has the well-known attributes of hot-melt adhesives.